Sonic polishing apparatus

ABSTRACT

INDUSTRIAL METAL PARTS ARE FINISHED BY PASSING THEM IN A CONTINUOUS FLOW PROCESS THROUGH A SONICALLY ACTIVATED CHAMBER CONTAINING SUITABLE GRIT MEDIUM.

9 H. E. M KINNEY SONIC POLISHING APPARATUS Filed March 6, 1968 5 K J 4mum m /f M II OSCILLATOR FIG.

FIG. 2

INVENTORI HOWARD E. McKlNN Y at Z ms AiroRNEY United States Patent SONICPOLISHING APPARATUS Howard E. McKinney, La Jolla, Calif., assignor toShell Oil Company, New York, N.Y.

Filed Mar. 6, 1968, Ser. No. 710,993 Int. Cl. B24b 31/00 US. Cl. 51-1631 Claim ABSTRACT OF THE DISCLOSURE Industrial metal parts are finishedby passing them in a continuous flow process through a sonicallyactivated chamber containing suitable grit medium.

BACKGROUND OF THE INVENTION The present invention relates to the art ofsonic finishing of industrial parts and pertains more particularly to acontinuous flow process of sonic finishing of industrial parts.

Industrial parts are fabricated by any number of means or methodsincluding casting, forging and machining. Parts emerging from any ofthese fabrication steps normally are rough, contain burrs and sharpedges and in the case of castings contain molding sand imbedded in thesurface thereof. These parts normally need finishing such as cleaning,deburring, edges rounded and polishing prior to further machining orassembly into machines. Many techniques have been used for cleaning andpolishing or finishing of these parts including hand scrubbing andgrinding. Other methods of cleaning and finishing of these parts includetumbling and shaking of the parts in a grit medium. The tumbling typefinishing operation is carried out by loading the parts in a barrel orbin type container which is partially filled with a grit medium and thentumbling the parts in the grit medium by rotating the container about ahorizontal axis. The shaking type finishing apparatus bodily shake orgenerally employs eccentric mass type shakers or vibrators to vibrate acontainer containing suitable finishing medium and parts. This type ofvibration requires massive shakers or vibrators to develop the necessaryforces involved in large batch type containers. The above-describedmethods of cleaning and finishing are time consuming and cannot keep upwith modern techniques for the production of industrial parts.

The present invention employs the principle of a resonantly vibratingsonic system for the introduction of high levels of sonic energy rapidlyand efficiently into a cleaning or finishing medium. The elasticresonant sonic vibration system of the present invention permits the useof a steady flow process of parts finishing wherein the parts go throughthe finishing chamber at such a rate as to obtain the desired finishingin a short period of time.

The energy transmitting system of the present invention employs aresonantly vibrating system which may be referred to as an acousticcircuit. For a better understanding of such systems, a close analogy maybe drawn between the acoustic circuit and an electrical circuit aspointed out, for example, in chapter 2 of Sonics by Heuter and Bolt,published in 1955 by John Wiley and Sons.

The present invention overcomes the foregoing problems in the prior artdevices and methods by providing a method and apparatus for a continuousflow process for sonic cleaning of industrial parts. The present systemcomprises a resonantly vibrating polishing chamber through which theparts pass in intimate contact with the polishing or finishing medium.

BRIEF DESCRIPTION OF THE DRAWINGS Many additional objects and advantagesof the present invention will be evident to those skilled in the artfrom Patented Oct. 5, 171

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the following detailed description and drawings wherein: FIG. 1 is aschematic illustration of a suitable layout for a system in accordancewith the present invention;

FIG. 2 is a side elevation partially in section of a preferredembodiment of apparatus for carrying out the present invention.

Description of the preferred embodiments With particular reference toFIG. 1 there is illustrated a schematic layout of a suitable system forcarrying out the present invention. As shown in FIG. 1 there isillustrated a conduit member 11 which is preferably constructed of asuitable elastic material, and forms a polishing chamber 12 throughwhich articles to be polished are passed in the cleaning process. Theconduit member may be of any suitable cross-section and may even be anopen channel or trough. A sonic oscillator 13 is operatively coupled tothe conduit member 11 to transmit elastic vibrations into a polishingmedium contained in its chamber 12. The oscillator 13 and elasticconduit member 11 form an elastic sonic energy transmission system whichwhen operated at or near its resonance frequency provides for the rapidand efficient delivery of energy to the polishing medium in the chamber.Parts 10a, 10b and to be polished pass, such as along a path 14, intochamber 12 wherein the polishing medium under the influence of sonicenergy impacts against and along the surfaces of the parts providingeffective cleaning and polishing thereof. The polishing medium, whichmay be any suitable type of abrasive particles such as an aluminumoxide, may be retained in a chamber 12 as the articles are passedtherethrough or in the alternative may be arranged so as to flowtherethrough substantially along with the articles. Moreover, provisionsmay be made for the recycling of the abrasive or polishing medium suchas along the path such as 15-. The polishing media may be of anysuitable type or composition to obtain the desired results. For example,the medium may comprise dry granules or may be slightly moistened asdesired. Also, the medium may be a slurry comprising abrasive particlessuspended in a suitable liquid. The level of polishing medium in chamber12 and the rate of flow therethrough of the medium as well as thearticles to be polished is preferably adjustable all independently inorder to obtain the proper degree of finishing.

In FIG. 2 is illustrated a suitable arrangement of apparatus of carryingout the present invention. As shown in FIG. 2 an elastic conduit member18 forms a polishing chamber 19 and serves to transmit energy from asonic vibration generator 20 into the polishing medium 16. Theoscillator 20 is coupled such as by means of a band or clamp 21 to theconduit member 18. The vibration generator 20 is preferably though notlimited to the oribiting mass type oscillator, such as disclosed in US.Pat. No. 2,960,- 314, issued to A. G. Bodine on Nov. 15, 1960. Theoscillator may be of the single roller type or twin roller type. With asingle roller type with its rotative axis parallel to axis of theelastic member 18 will undergo a gyrating elastic standing wave motioncharacteristic of an elastic standing wave pattern with the ends andcenter of the tube undergoing a gyratory motion. A lateral standing modeof vibration may be obtained by the use of dual roller oscillator havingcounter-rotating rollers or by the use of a single roller oscillatorhaving its rotative axis perpendicular to the conduit member 18.Suitable means such as a hopper or chute 22 is utilized for feeding orconveying the polishing medium 16 and parts 17a, 17b and 17c to thepolishing chamber 19. The hopper 22 is preferably vibrationally isolatedfrom conduit member 18 such as by means of a resilient or elastomericring 23 held in place such as by expandable metal bands 24 and 25.

At least some portion of the flow path of the present invention ispreferably tilted to provide a continuous gravity feed of the materialsthrough the polishing chamber. Of course, other methods of inducingflow, such as pumping may be utilized to maintain a suitable rate offlow through the polishing chamber. The apparatus illustrated in FIG. 2is supported from suitable support means such as the base member 26 fromwhich extends a vertical strut member 27. The elastic conduit member 18is preferably supported at nodal points by suitable vibration-isolatingmeans such as an elastomeric band 28- surrounded by band member 29 whichis in turn pivotly supported by pin 30 to strut 27. A second elastomericband 33 and metal band 34 encircle the elastic conduit 18 in thevicinity of the upper nodal point and is in turn pivotally connected bypivot pin 35 to an extendible support member such as fluid transducer 36which is in turn pivotally supported by pivot pin 38 to base member 26.A conduit 39 extends to a suitable source (not shown) of hydraulic fluidfor operating the fluid motor 36. The above-described support structurepermits the adjustment of the tilt of the conduit 18 and consequentlythe rate of flow as well as the volume of material in a chamber 19 at agiven moment. The rate of flow will determine the residence time orlength of time spent in the chamber by the part. A high degree offilling of the polishing chamber 19 with polishing medium provides abetter sonic coupling of the energy from the conduit 18 into thepolishing medium in chamber 19 and consequently an increased rate offinishing and polishing of the parts fed therethrough. A suitable bin 45is located at the discharge end of conduit 18 to catch the polishingmedium upon its discharge from the polishing chamber. The parts may bepermitted to fall in a heap with the polishing medium from which it isthere retrieved or they may be preferably caught by means of a conveyorbelt or chain 46 which permits an unrestricted flow of the polishingmedium therethrough into the bin 45. The conveyor 46 is supported suchas by means of roller 47 and driven by suitable means not shown.Suitable guide panels 48 and 49 supported by means of a strut 50 extendalong the sides of the conveyor belt or chain 46.

While the invention has been described in detail with respect tospecific embodiments, it Will be apparent to those skilled in the artthat various changes and modifications may be made without departingfrom the spirit and scope of the' invention as defined by the appendedclaim.

I claim:

1. An apparatus for finishing parts in an abrasive finishing medium,said apparatus comprising:

a tubular elastic finishing chamber located in a conduit and adapted forreceiving a continuous flow of said parts and said finishing medium;

an orbiting mass sonic oscillator directly operativel coupled to saidfinishing chamber without intervening resonating members in a manner soas to resonantly vibrate said chamber in a gyratory standing wavemotion; the chamber being acoustically isolated from the remainder ofthe conduit by elastomeric material connecting the chamber to theconduit; and feeding means for continuously feeding said parts throughsaid chamber, the chamber being tiltable to adjust the rate of flow ofparts and medium therethrough.

References Cited UNITED STATES PATENTS 2,967,434 1/1961 Mahlfeldt 51-7UX 3,380,195 4/1968 Bodine 51-7 2,796,702 6/1957 Bodine 517 2,208,0777/1940 Linke 51-7 UX 3,336,701 8/1967 Moore 51-7 3,496,677 2/1970 Bodine517 HAROLD D. WHITEHEAD, Primary Examiner

